Incandescent electric lamp



(No Model.)

W. E. NICKERSON.

INQANDESGENT ELECTRIC LAMP. N0. 507,556. Patented Oct. 31, 18931WITHEESYESI- I l l\|- @2 36? art/WM UNITED STATES PATENT OFFI E.

WILLIAM EMERY NIOKERSON, OF CAMBRIDGE, MASSACHUSETTS.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 507,556, dated October31, 1893.

Application filed July 31,1893.

To all whom it may concern.-

Be it known that I, WILLIAM EMERY NICK- ERSON, of Cambridge, in thecounty of Middlesex and State of Massach usetts, have invented a new anduseful Improvement in Incandescent Electric Lamps, of which thefollowing, taken in connection with the accompanying drawing, is aspecification.

My invention relates to incandescent elec tric lamps of that class inwhich disks of mica are used, either for supporting a plug of fusiblecement by which the neck of the lamp bulb is sealed air-tight, or forthe purpose of intercepting and reflecting back, or away, from the saidplug, the radiant heat of the filament, which would otherwise tend tosoften it.

It consists in a method of rendering such disks of mica more effectivein intercepting such radiant heat.

My invention is illustrated in the accompanying drawing, in which Arepresents the glass bulb of an incandescent electric lamp of the classdescribed, F the filament, W W the leading-in wires to which thefilament is attached at f f.

P is a plug of fusible cement which is poured into the lamp neck in amelted state and is supported while soft by the disk E which rests uponthe shoulder a formed in the neck of the lamp bulb.

B is a base or cap of an ordinary type, secured to the lamp neck byplaster of paris in the usual manner, and to the proper parts of whichthe leading-in wires W W are attached at S S.

D is a heat-reflecting disk made of mica and rests upon the shoulder a,from which it is prevented from rising by the coils O 0 formed in theleading-in wires W W directly above it.

My invention relates to a method of rendering the disk D, and also ifdesired the disk E, more effective in intercepting and throwing back theradiant heat of the incandescent filament. This I accomplish bysubjecting these mica disks, to a high temperature, such as may beobtained by holding them in the flame of an ordinary Bunsen gas lamp.The result of this treatment is to cause the thin laminae of which themica is composed, to

Serial No. 482,003. (No model.)

separate from each other to such an extent, that the thickness of thedisk is much increased, and an extremely large number of narrowlyseparated surfaces presented, for the backward reflection of the heatrays. So great is the number of these surfaces that the disk becomesopaque, or at least merely translucent, and totally non-diathermatic.Its capacity for transmitting heat by conduction is also reduced to aminimum, and it becomes extremely efficient, in protecting the cementplug P, from the destructive efiects of the radiant heat of theincandescent filament.

I claim- 1. In an incandescent electric lamp, having a bulb the neck ofwhich is adapted to be closed air-tight by a plug of fusible cement,mica disks located between the cement plug and the filament, said diskshaving been subjected to a high degree of heat, for the purpose ofincreasing their capacity to intercept heat rays, substantially as andfor the purpose set forth.

2. In an incandescent electric. lamp, the combination of the glass bulbA having a neck adapted to be closed air-tight by a plug of fusiblecement, the cement plug P, the

leading-in wires W W, and the filament F; with the disk of mica D, saiddisk being rendered opaque by the separation of its laminae through theeffect of heat, substantially as and for the purpose set forth.

3. In an incandescent electric lamp, the combination of the glass bulb Ahaving a neck adapted to be closed air-tight by a plug of fusiblecement, the cement plug P, the leading-in wires W W, and the filament F;with the disk of mica E, said disk being reudered opaque by theseparation of its laminae through the efiect of heat, substantially asand for the purpose set forth.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 28th day of July, A. D.1893. 7

WILLIAM EMERY .NICKERSON.

Witnesses:

FRANK G. PARKER, FRANK G. HATTIE.

